1. Field
The present disclosure relates to graphene-based optical devices, and more particularly, to a graphene-based photodetector including a complex transparent electrode, a method of manufacturing the graphene-based photodetector, and a device including the graphene-based photodetector.
2. Description of the Related Art
Photodetectors are devices that generate electrical signals by receiving light and detecting the intensity of light, and are widely used in optical communication networks, precision measuring equipment, and the like. Recent communication networks, that is, the fourth generation of communication networks, generally operate at terahertz speeds such that high capacity data including moving images may be substantially rapidly processed. Thus, components used in communication networks have been improved to have a structure for high speed and high capacity processing.
In graphene, the effective mass of electrons and holes are close to zero at the Dirac point. Accordingly, theoretically, carriers may move at 1/300 of light speed in graphene. And thus, graphene has higher mobility than materials known previously. In addition, the energy bandgap of graphene is about zero (0) electron volt (eV) in the Dirac point. Thus, graphene may absorb light substantially in an entire wavelength band, and thus, may allow broad band transmission. As a result, a photodetector including graphene may transmit high capacity data at high speed.
Conventional photodetectors have an asymmetrical structure in which an energy band is asymmetric due to two different metal electrodes that are used for measuring photocurrent. Due to this energy band structure, a photocurrent may be increased. However, energy conversion efficiency is substantially low in a conventional photodetector including graphene, and thus, the intensity of a detection signal may be substantially low.